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#include <stdint.h>
#include "assert.h"
#include "util.h"
#define VGA_WIDTH 80
#define VGA_HEIGHT 25
struct e820_entry {
uint64_t base;
uint64_t length;
uint32_t type;
uint32_t ext_attr;
};
STATIC_ASSERT(sizeof(struct e820_entry) == 24, e820_entry);
struct vga_term {
uint16_t *buf;
uint16_t column;
uint16_t line;
};
static void
vga_term_scroll(const struct vga_term *const term)
{
for (int i = 0; i < VGA_HEIGHT-1; ++i)
for (int j = 0; j < VGA_WIDTH; ++j)
term->buf[i*VGA_WIDTH+j] = term->buf[(i+1)*VGA_WIDTH+j];
for (int i = 0; i < VGA_WIDTH; ++i)
term->buf[(VGA_HEIGHT-1)*VGA_WIDTH+i] = 0x0f20;
}
static void
vga_term_newline(struct vga_term *const term)
{
if (term->line < VGA_HEIGHT-1)
++term->line;
else
vga_term_scroll(term);
term->column = 0;
return;
}
static void
vga_term_putc(struct vga_term *const term, const char c, const uint8_t color)
{
if (c == '\n') {
vga_term_newline(term);
return;
}
if (term->column >= VGA_WIDTH)
vga_term_newline(term);
term->buf[term->line*VGA_WIDTH+(term->column++)] = (color<<8)|(c);
}
static void
vga_term_puts(struct vga_term *const term, const char *const str, const uint8_t color)
{
for (int i = 0; str[i]; ++i)
vga_term_putc(term, str[i], color);
}
static void
vga_term_print_hex(struct vga_term *const term, uint64_t num, const uint8_t color)
{
vga_term_putc(term, '0', color);
vga_term_putc(term, 'x', color);
for (int i = 0; i < 16; ++i) {
char c;
c = (num >> 60);
c = (c < 0xa) ? (c + '0') : (c + 'a' - 0xa);
vga_term_putc(term, c, color);
num <<= 4;
}
}
void
kmain(void)
{
vga_cursor_hide();
struct vga_term term = {(uint16_t *)0xb8000, 0, 0};
for (int i = 0; i < VGA_WIDTH*VGA_HEIGHT; ++i)
term.buf[i] = 0x0f20;
vga_term_puts(&term, "ProvidenceOS v0.1\n\ne820 memory map:\n", 0x0f);
const uint16_t e820_size = *(uint16_t *)0xf000;
const struct e820_entry *const e820_mmap = (struct e820_entry *)0xf008;
for (uint16_t i = 0; i < e820_size; ++i) {
vga_term_print_hex(&term, e820_mmap[i].base, 0x0f);
vga_term_putc(&term, '-', 0x0f);
vga_term_print_hex(&term, e820_mmap[i].base + e820_mmap[i].length - 1, 0x0f);
vga_term_putc(&term, ' ', 0x0f);
vga_term_puts(&term, e820_mmap[i].type == 1 ? "available\n" : "reserved\n", 0x0f);
}
halt();
}
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